Field of the Invention
The present invention relates to a terminal module for electrically connecting electric elements mounted on a heat radiation board to an electrical circuit board in a power module to be equipped in an automobile, such as an engine control unit (ECU) and a power control unit (PCU).
Description of the Related Art
FIG. 68 is a perspective broken view of a conventional part unit.
As illustrated in FIG. 68, a power module to be equipped in an automobile, such as an ECU and a PCU, is generally designed to include a part unit 900 including a heat radiation board 902 on which a plurality of electric elements 901 is mounted, a frame 904 on which a plurality of electrically conductive terminal 903 is mounted in a comb-like manner, and a circuit board 906 formed with a plurality of through-holes 905 and having electrical circuits (not illustrated) thereon. In the part unit 900, the electrically conductive terminals 903 electrically connecting the electric elements 901 mounted on the heat radiation board 901 to the through-holes 905 formed at the circuit board 906 are compressively inserted into the frame 904 sandwiched between the heat radiation board 902 and the circuit board 906, or assembled into the frame 904 by insertion process while the frame 904 is being made. Thus, the electrically conductive terminals 903 are integral with the frame 904.
Japanese Patent Application Laid-open on No. 2013-211499 discloses a power module, a terminal to be used in the power module, and a method of fabricating the power module.
The part unit 900 illustrated in FIG. 68 is accompanied with a problem in that if the frame 904 is designed to be large in size, the frame 904 would be likely to be curved and/or deformed with the result of deterioration in accuracy of flatness thereof, causing a defect in bonding between the electrically conductive terminals 903 mounted on the frame 904 and the electric elements 901 mounted on the heat radiation board 902. Furthermore, shrinkage of a synthetic resin of which the frame 904 is made causes deterioration in accuracy in positioning of the electrically conductive terminals 903.
When the frame 904 with which the electrically conductive terminals 903 are integrally assembled is fabricated by an insertion molding process, a mold used for an insertion molding process is usually amended by a plurality of times in order to enhance a pitch and/or accuracy of flatness in the electrically conductive terminals 903. However, since the electrically conductive terminals 903 are individually mounted on the frame 904, it is quite difficult or almost impossible to amend a mold, resulting in that the mold might not be amended in a desired manner.
It is known that the frame 904 made of a resin thermally shrank in a small degree or a resin providing preferable performance as a filler is able to enhance a pitch and/or accuracy of flatness in the electrically conductive terminals 903. However, such a resin brings cost-up in the fabrication of the frame 904, and accordingly, it is not actually allowed to use such a resin for fabrication of the frame 904.
The process of fabricating a power module disclosed in the above-identified Japanese Patent Application is considered to be accompanied with the problems as mentioned above.